Kenichi Yamamoto (山本 健一, Yamamoto Ken'ichi; March 5, 1925 – February 4, 1982) was a Japanese yakuza boss who founded the Yamaken-gumi, the largest and most powerful affiliate gang of the Yamaguchi-gumi, Japan's largest crime syndicate. By the time of his death, Yamamoto had risen to the rank of wakagashira (the number-two boss) and was considered the heir apparent to the Yamaguchi-gumi's third godfather, Kazuo Taoka.
Source: “Kenichi Yamamoto (yakuza)”, English Wikipedia (CC BY-SA 4.0), excerpt